Beyond the Lena, Bunbury has a set of offshore reefs that few visitors know about. Octopus Garden Dive Charters lists them by name on its dive page: Blade Coral Reef at 30-33 m (Advanced Open Water required), the Horseshoe Coral Reefs and Lena Coral Reef at 15-20 m, Trevor's Horseshoe Reef at 15 m, Gibbs South Reef formation, Peter's North and South Reefs and the Leather Jacket Caves at 10-12 m, and coral lumps north of Bunbury, at 'The Huts' and off Peppy Beach at 10-18 m. The operator also runs trips to Busselton's Four Mile Reef and the Busselton Jetty.

The names indicate what to expect: hard and soft coral growth on limestone reefs and lumps (the Leeuwin Current carries warm water and coral larvae down this coast), with ledges and small caves in places. Geographe Bay's reefs are known for colourful sponges, corals and nudibranchs, and larger fish such as pink snapper, dhufish, samson fish and wobbegong sharks are possible.

Because the only published information is the operator's list of sites and depths, the sites are grouped here in one record; individual descriptions and positions should be obtained from Octopus Garden. They suit Open Water divers on the shallower reefs and Advanced divers on Blade Coral Reef, and offer a good second dive after the Lena on a Bunbury charter.

Geographe Bay is unusual on the WA coast because it faces north, so the prevailing south-westerly swell and sea breeze that close the ocean coast are largely blocked by Cape Naturaliste. That shelter, plus the warm Leeuwin Current, is what makes the bay's reefs, jetties and wrecks diveable for much of the year, and why winter north-westerly storms are the main thing that shuts it down.

Octopus Garden Dive Charters departs Casuarina Boat Harbour, Bunbury, at 8.30 am and returns by 1.30 pm on a 36-foot boat taking up to 10 guests. The reefs lie offshore to the north and west of Bunbury; positions are held by the operator. Boat ramps along Geographe Bay include Bunbury (Casuarina), Busselton, Port Geographe, Quindalup and Dunsborough; on the Capes coast the Canal Rocks, Gracetown and Hamelin Bay ramps are small and swell-exposed.

Check the forecast, carry a marine radio and log a trip plan with the local Marine Rescue group.

Northern Geographe Bay is sheltered from the south-west but exposed to north-westerly winds and winter storms; Octopus Garden operates October-April, weather dependent. Calm easterly mornings are best. General pattern in Geographe Bay: sheltered from south-westerly swell by Cape Naturaliste; summer mornings are calm before the afternoon sea breeze, while winter north-westerly fronts roll swell and chop into the bay and reduce visibility for several days.

Follow the operator's brief: typically descend on a shot or anchor, explore coral lumps and ledges at 10-18 m (or 30-33 m on Blade Coral Reef), and ascend the line. Agree a turn pressure before descending (half gas, or a third where current is likely), carry a DSMB, and make a 3-minute safety stop at 5 m.

Octopus Garden Dive Charters (Bunbury) - mainly October to April, weather permitting. Blade Coral Reef (30-33 m) requires Advanced Open Water.